Sump tank including pump



March 26, 1963 R. R. MCMATH SUMP TANK INCLUDING PUMP Filed June 17. 1960 ATTORNEY United States Patent O 3,082,784 SUMP TANK INCLUDING PUMP Robert R. McMath, Chelmsford, Mass., assignor to United Aircraft Corporation, East Hartford, Conn., a corporation of Delaware Filed June 17, 1960, Ser. No. 36,878 6 Claims. (Cl. 137-207) This invention relates ot liquid-circulating systems for use in aircraft and particularly to sumps and sump tanks especially adapted for use in such airborne systems. One important application of the invention is in connection with liquid-metal-circulating systems which may be used in nuclear powerplants for aircraft although the invention is in nowise limited to this use.

In a nuclear powerplant, for example, it is desirable to have an in-the-line sump tank for the reason of flexibility of installation in an airplane. In general, such a sump tank must be mounted at the highest part of the fluid system.

The sump tank of this invention is intended for use in a liquid-circulating system in which no entrained vapor is permissible. At the same time the liquid must be in contact with a gas for pressurization of the system and to provide means for absorbing changes in liquid volume due to temperature changes.

Accordingly, it is an object of this invention to provide in a liquid-circulating system a sump tank which serves as an expansion tank to compensate for in-flight temperature changes in a liquid.

Another object of this invention is to provide a sump tank having means for the gas pressurization of the system.

Still another object of this invention is to provide such a sump tank having means for degassing the liquid in a system prior to its admission to the sump pump.

A further object of this invention is to provide a sump tank which provides sufficient liquid capacity to compensate for small losses in the piping system due to leakage.

These and other objects and advantages of this invention will become evident or will be specically pointed out in connection with the following description of a preferred embodiment of the invention shown in the accompanying drawing. In this drawing:

FIG. 1 is a plan view, partly in section, taken on line 1-1 of FIG. 2; and

FIG. 2 is a longitudinal sectional elevation taken on lines 2-2 of FIG. 1.

The sump tank of this invention includes an outer casing having an oval side wall 10 and top and bottom walls 12 and 14. The side wall 10 is provided with an internal peripheral shoulder 16 adjacent the bottom wall to form a seat for an oval perforated plate 18 which forms a chamber 20 at the bottom of the tank.

The cover 12 is adapted to be secured to the side walls 10 in a fluid-tight manner and to this end has its periphery 22 overlying the side walls 10 at which a suitable fluid-tight seal is maintained. As herein shown, the sump tank contains two pumps 24 and 26.

The pumps are enclosed within inverted bell-shaped housings 34 and 36, respectively, which consist of lower annular chambers 38 and 40 and upper smaller diameter chambers 42 and 44. These inverted bell-shaped housings 34 and 36 have their open bottoms resting directly on and enclosing a portion of the perforated plate 18.

Pump 24 has a discharge pipe 50 which extends downwardly through a circular aperture in plate 18 and through the bottom wall 14. Preferably, this discharge pipe is welded to the bottom Wall 14 to make a Huid-tight connection. Pipe 26 has a similar discharge pipe 52. Fluid enters the sump tank through three inlet pipes 54,

K 3,082,784 Patented Mar. 26, 1963 ice 56 and 58, which extend through the side wall 10 of the tank into chamber 20 beneath the perforated plate. The return duct 60 of a bypass line also extends through the bottom wall 14 in the center of the tank and discharges itno chamber 20. This duct is also welded to the bottom wall 14 of the tank. Fluid in the tank is adapted to occupy some level approximately midway between the perforated plate 18 and the cover 12. This liquid level is shown herein at 62.

The liquid in the system is pressurized by an inert gas which is admitted through pipe 64. This pipe extends through the top wall of the tank to which it is welded. Gas passages 45 are provided in the bell-shaped housings 34 and 36 near the upper end of the upper reduced diameter chambers 42 and 44 therein. Thus, wherever the liquid level may be it is acted upon equally by the gas both inside and outside of the housings 34 and 36. The iluid inlet to pump 24 is shown at 68, and the inlet to pump 26 is shown at 70. These inlets, it will be noted, are above the perforated plate 18 and within the housings 34 and 36.

In operation, uid enters pumps 24 and 26 through inlets 68 and 70, the uid entering the pumps coming from chambers 38 and 40 within housings 34 and 36. This iiuid is discharged by the pumps through discharge pipes 50 and 52 and after circulating through the systems returns through inlet pipes 54, `56 and 58. The sump tank, accordingly, is what is known as an in-line installation and, as previously stated, occupies the highest point in the liquid system. This gives the greatest exibility in installing the sump tank in an airplane. Insert gas admitted through pipe `64 acts on the entire free surface of the liquid in the tank, gas being admitted to chambers 42 and 44 through passages 45.

By reason of the location of the pump inlets 68 and 70 in the undisturbed liquid above the perforated plate 18, the liquid taken into the pumps is degassed prior to its admission to the pumps. Also, the tank 10` serves as an expansion tank and provides additional capacity to compensate for small leakage in the piping of the system.

A further advantage of the sump tank of this invention resides in the ability to pressurize the fluid system with an inert gas.

While only a single embodiment of the invention has been shown and described herein, it will be evident that many changes may be made in the construction and arrangement of the various parts without departing from the scope of the appended claims.

I claim:

1. In combination, a liquid-metal-circulating system including a sump tank, a perforated plate supported in said tank in spaced relation above the bottom wall of said tank and parallel therewith, an inverted bell-shaped pump casing having its open end resting on said plate, a pump in said casing having a uid inlet within said casing above said perforated plate and having a tluid outlet extended through said plate and through the bottom wall of said tank, and a liquid inlet to said tank discharging liquid between the perforated plate and the bottom Wall of said tank.

2. A liquid-metal-circulating system as claimed in claim 1 in which the iluid in the tank is pressurized by an inert gas.

3. A liquid-metal-circulating system as claimed in claim 2 in which the tank occupies the highest point in the system and the inert gas serves to pressurize the liquid in the system.

4. A liquid-metal-circulating system as claimed in claim 2 in which the return pipe from a bypass line enters the tank through the bottom wall and discharges uid into the space beneath the perforated plate.

5. In a liquid-metal-circulating system, a sump tank comprising a pressure-tight enclosure, a perforated plate in said tank supported in spaced parallel relation above the bottom wall of the tank, an inverted bell-shaped pump casing having its open and resting on said perforated plate, a pump in said casing having a tluidinlet inside said casing and having a iluid outlet duct extending through said plate and the bottom of said tank,a fluid inlet to said tank beneath said plate, and means for admitting inert gas under pressure at the top of said tank to pressurize the liquid metal in said system.

6. In combination, a liquid-metal-circulating system including a sump tank having top, bottom and side walls, a perforated plate in said tank between said top and bottom walls dividing said tank into an inlet chamber below said plate and a pump chamber above said plate, a liquid inlet pipe for said tank discharging into said inlet chamber, an inverted bell-shaped pump casing open at the bottom having its open bottom seated on said plate and enclosing a portion of the perforated area of the latter, a

pump in said casing having a liquid inlet within said casing above said perforated plate and having a discharge pipe extended through said plate and through the bottom wall of said tank, and means for pressurizing the liquid in said tank including a pipe introducing gas under pressure to the top of said tank.

References Cited in the file of this patent UNITED STATES PATENTS 

1. IN COMBINATION, A LIQUID-METAL-CIRCULATING SYSTEM INCLUDING A SUMP TANK, A PERFORATED PLATE SUPPORTED IN SAID TANK IN SPACED RELATION ABOVE THE BOTTOM WALL OF SAID TANK AND PARALLEL THEREWITH, AN INVERTED BELL-SHAPED PUMP CASING HAVING ITS OPEN END RESTING ON SAID PLATE, A PUMP IN SAID CASING HAVING A FLUID INLET WITHIN SAID CASING ABOVE SAID PERFORATED PLATE AND HAVING A FLUID OUTLET EXTENDED THROUGH SAID PLATE AND THROUGH THE BOTTOM WALL OF SAID TANK, AND A LIQUID INLET TO SAID TANK DISCHARGING LIQUID BETWEEN THE PERFORATED PLATE AND THE BOTTOM WALL OF SAID TANK. 